NOTE: Forms can't send PUT and DELETE request

• GET /:
  • redirect to /articles
• GET /articles
  • list all published articles
• GET /articles/:slug
  • read an article (only if it's published)
• GET /admin
  • basic authentication
  • redirect to /admin/articles
• GET /admin/articles
  • list all articles
  • display an input to create new article with a title
• POST /admin/articles
  • save new article title
• GET /admin/articles/:slug
  • display the form editor fill with existed data
• POST /admin/articles/:slug?action=edit
  • save the edited data
• POST /admin/articles/:slug?action=delete
  • delete an article